Stealth, Radars and Discussions on 5th Generation Technology

[p2prada]

Then all the Russians has to do is to deploy just a couple of F-117 equivalent demonstrators. Not an active duty squadron, just a couple of actually flight capable F-117 equivalent aircrafts. The low observability of the F-117, F-22 and B-2 are well known to air traffic controllers. These aircrafts flies with transponders, like the type civilian airliners uses, to enhance their radar returns and to mask their true RCS values.

The above facility is called a 'radar range'. This is where full scale models are tested for their radar returns from various angles.

That is an upside-down test of the A-12/SR-71. Note the vertical stabs are not installed. Why upside-down and no vertical stabs? Depends on the testing criteria on that day. They could be testing for the radar returns on the underside of the aircraft. We do not know. The point here is that the US have extensive knowledge and experience at conducting RCS testing even before the first flight. Radar ranges are often mistaken for airports because of the long strips of concrete. Without full scale facilities like a radar range, the less certainty we have about the radar cross section of a design.

For the Russians and the Chinese...Either put up or shut up.

Eg: In India we do not use full scale replicas for wind tunnel testing. We use computers and a small scaled model. You can carry it around.

Possibly a RLV.

Wind tunnel model of a MCA. Concept and not the real one. Probably used to test the F-22 or F-35 aerodynamics.

 

[Sridhar]

Stealth,radars and discussions on 5TH generation technology

Saturday, October 10, 2009

The new Russian anti-radar materials

​

The Russian researchers go further for developing more advances compounds and technologies for an anti-radar covering. As it's well known, the airframe and the shipframe stealth geometry gives only a partial answer for the contemporary radar development. Only the centimeter and millimeter long radar waves are effectively deflected by such method while the L-band radars progress is remained the growing treat for military devices. Other complimentary methods are composite use and covering.



The usually used antiradar materials are the resins and paints with ferromagnetic. The new nano-metric anti-radar covering is much more light and stable. It's made with magneto-dielectric layering 2-80 nm thick on a high temperature-steady material. The radar-absorption is about 10 Db in 8-80 GHz diapason, i.e. lg (P1/P2) = 1, while P1 – is the incoming radar power and P2 – the reflected. By the formula with these materials the RCS can be reduced 10 times. Its relative mass is as 1 – 1.5 kg/m2. High resistance against climatic factors is provided. They have the one-layer structure instead of usually 5-6.



This new technology can be used not only for RCS reducing, but for side-lobe radiation reducing on the radars, raising their effectiveness. The military electronics can be defended from radio splashes and an unsanctioned communication access by this way. Personal isolation from the dangerous radar microwaves can be provided too by this method.



The potential of this technology allows creating ant-radar materials with working diapason of 1 – 300 GHz. The implementation of it on the 4th+ generation fighters' fleet could prolong its service while the 5th generation planes are yet to be produced or too costly for some customers.

Defunct Humanity: The new Russian anti-radar materials

 

[gambit]

Such a facility is no longer required. Computers can perform these functions easier much better than the time consuming process of testing using the "older" methods.

We are more than willing for you to believe that.

 

[gambit]

Will faster processing not solve this problem? AESAs are meant to preform better classification of targets too.

There will always be a clutter threshold rejection point. Take Moving Target Indicator radar for example. The MTI processor will process only the Doppler component of whatever the radar pick up. Same for radar altimeter. Each discrete function will focus only the component that you command. There are too many background noise.

Out of the topic. I believed the other parts of the bird cannot be detected easily because they are organic rather than their distinct shape.

At the same time, can a sky diving human be detected by a radar? Consider he is in his birthday suit.

It is not the organic matter. It is a combination of target size, composition, and freq used. The proper combination will pick up organic matter.

Will doppler resolution not solve the same problem again? Nothing in the air flies faster than an airplane, and definitely not a bird(max 200km, probably lesser).

It may...But if there is no movement, there will be no Doppler resolution. So if by luck that you happen to detect a bird-sized target that is moving at 700km/h against a clear background, all of a sudden a flock of birds take flight, now you have many Doppler signals available. Somewhere in there is one that is traveling at 700km/h but there is no reliable way for you to tell if the next point of that target's travel is not a new bird but the target itself. Further, the F-22 and F-35 is self aware of its RCS value with respect to the transmitter position and angle, meaning once it detect the location of the transmitter, it will call upon its own dimensions, calculate the RCS value and if necessary, it will slightly alter its flight attitude slightly to reduce that value.

Sir, how do you rate the 2 birds? My opinion is the F-22 is more stealthy, faster, more agile etc; but it will be the F-35 which will be the superior fighter considering its avionics.

I know that people are desperate for information, if anything it is so that they can attempt to downplay the threat but it is too early to tell.

Also, how will 2 stealth platforms engage each other? Let's say Greece and Turkey have F-35s and they are at war. How will the F-35 engage the other F-35. Consider both have the same avionics and the pilots have the same skill level.

No such thing as pilots having the same skill levels. Even mechanical objects that man create have their distintive 'personalities' due to imperfections in their construction. You need to talk to automobile or aviation mechanics and they will tell you all kinds of stories on how one machine just happened to be more problematic than the rest.

Are you referring to active cancellation or plasma stealth or something more elusive?

We already have some measures of active cancellation. But the natural progression of cancellation would be to control the wave's properties once it impact the body, not merely negate it. And please dismiss that 'plasma stealth' nonsense. It is something the Russians cooked up to make themselves look good. Plasma have its own properties and detectors can be created to process plasma derived emissions. Look up what is plasma and what it produces besides heat.

 

[Vladimir79]

You mean the Soviets were so innocent of the same? Wonder who got the USSR on the fast track to becoming a nuclear weapons state. Got news for you, tovarisch, not trying to downplay Ufimtsev, but what he did was to create the predictive equations, he did not discover the behavior itself, which was discovered prior to WW II, which ended with the world's first wide deployment of a functional radar system -- Chain Home and Chain Home Low -- which gave Britain the edge over the Germans. If it was not Ufimtsev, it would have been someone else. In fact, there are credible evidences that the equations were co-created, albeit at different countries, because the behaviors are the same in communication. Ufimtsev happened to have a large organization, the Soviet academic institution, to publish and professionally archived his knowledge.

CCCP didn't develop the Tsar Bomba by stealing ideas... good old Russian ingenuity. Ufimtsev laid the scientific base for stealth technology, of which Amerikans used. Good on ya for being able to use it, but don't forget where it came from.

The F-117's method is effective but dated. You can make all the claims you want out of nationalistic pride, but -- put up or shut up.

F-117 was a maintenance nightmare and vulnerable to 1960s SAMs which led to its early retirement. The B-2 is so costly the production run was stopped at 21 and suffers its own maintenance problems. The F-22 certainly is more advanced than even PAK FA will be, but it is so costly it has led to an early production shutdown. F-35 cost spiral is out of control. You have been unable to mass produce a cost efficient stealth airframe. As it stands today, you have failed to transform the USAF into the fifth generation and the future of F-35 is not looking good.

From the latest Dutch procurement report...

"The cost growth of 38% and the doubled life cycle cost since 2001 makes the F-35 less affordable than predicted. All these factors are interacting with each other, as a deadly embracing. Lower quantities mean loss of economy of scale, that will bring higher prices, the start of a downward spiral in the F-35 program." http://new.isoshop.com/dae/dae/articles/communiques/JSF_MARKETANALYSIS_JOBO.pdf

For all your great technology, prices go up and lifecycle costs double... another failed US stealth project. Your nationilastic pride seems to have gotten the better of you.

We pay Russia to launch because our REUSABLE SPACE VEHICLE fleet is worn out, not because we are behind Russia in space technology. The future is in reusable launch vehicle (RLV), not in expendable (ELV). An RLV is infinitely more versatile than an ELV. Our experience in this will allow the US to build the next generation of RLV that will be more capable than the current shuttle fleet design and keep US several steps ahead of Russia. This is about finance, not technology or experience.

We already invented an RLV, the first remotely operated in history. The cost efficiency of such a device discounted it. If NASA wanted too, they could have built more shuttles, but they didn't do to cost. Now they will have to pay us in our ELVs to get them into space... how ironic.

Russia entered this 'market' out of dire financial necessity. It demean the Russian military, as if the state of the Russian military is not sorry enough already.

Considering it was founded in 2002, when our economy flourished, your claims are baseless. It demeans no one and gives people the chance to experience a one in a lifetime adventure. I really don't understand your disdain for the Russian military.

Your flight in the -31 will be enjoyable, I am certain, but I doubt that it will be more interesting than what I had in the F-111. We flew hard ride terrain following (TF) over the English hills and later simulated a very low altitude bomb run over the Channel for the French to test their radars. We flew at 50ft over the water and I set the TFRs sensitive enough to pick up surface waves. It made for a very choppy flight. French air defense never pick our flight up until we broke horizon, which usually is weapons release. Then we had an air refueling stop before returning to Upper Heyford.

F-111s... you must be an old timer.

 

[gambit]

CCCP didn't develop the Tsar Bomba by stealing ideas... good old Russian ingenuity. Ufimtsev laid the scientific base for stealth technology, of which Amerikans used. Good on ya for being able to use it, but don't forget where it came from.

Even though everyone expects credit given when/where it is due, everyone also pay more respects for the final products than the origins of the ideas that birthed those products. When people see the F-117, F-22, F-35 and the B-2 in flight, they will not call out Ufimtsev's name in awe, they will see those aircrafts as American products. For those who are in the aviation business, specifically avionics, specifically radar, they will mentally pay their respects to Ben Johnson.

F-117 was a maintenance nightmare...

I crack up everytime someone say that, usually they lifted it off some press reports whose reporters have not even a shallow understanding of aviation.

...and vulnerable to 1960s SAMs which led to its early retirement.

Not this nonsense again. The F-117 first flight was in 1981, flown in secret for about a decade, then public disclosure, then retirement in 2008. The Serbian lucky shot of one F-117 was in March 1999. The YF-22 first flight was in 1990, the same year as the YF-22 and YF-23 fly-off competition. So when you said 'early retirement' it is 'early' compared to what standard? The F-16 has been around for over thirty years, is that the standard? According to whom? Russia? Even without installed weapons system, the F-22 as a low observable aircraft was clearly the superior to the F-117 nearly a decade before the Serbian lucky shot of that one F-117.

Facts...The same level or lower RCS, superior maneuverability in all flight regimes, supercruise while the F-117 was subsonic, a superior AESA radar system whereas the F-117 has no radar, superior pilot vision, superior avionics...In other words, the F-117's retirement was inevitable even before March 1999, the time of the Serbian lucky shot. I do not know the origin of this 'early retirement' nonsense and really I do not care, but all it takes is less than five minutes checking out publicly available information on them and another five minutes to do some critical thinking and it would be clear to see the absurdity of that 'early retirement' argument.

As for the claim that the F-117 is 'vulnerable' to long wavelengths, I have already debunked that notion a while ago. Those who made that argument that desperate people quickly latched onto have not a clue about radar detection.

The B-2 is so costly the production run was stopped at 21 and suffers its own maintenance problems. The F-22 certainly is more advanced than even PAK FA will be, but it is so costly it has led to an early production shutdown. F-35 cost spiral is out of control. You have been unable to mass produce a cost efficient stealth airframe. As it stands today, you have failed to transform the USAF into the fifth generation and the future of F-35 is not looking good.

From the latest Dutch procurement report...

"The cost growth of 38% and the doubled life cycle cost since 2001 makes the F-35 less affordable than predicted. All these factors are interacting with each other, as a deadly embracing. Lower quantities mean loss of economy of scale, that will bring higher prices, the start of a downward spiral in the F-35 program." http://new.isoshop.com/dae/dae/articles/communiques/JSF_MARKETANALYSIS_JOBO.pdf

For all your great technology, prices go up and lifecycle costs double... another failed US stealth project. Your nationilastic pride seems to have gotten the better of you.

Right...The only thing Russia can do is gloat about the cost when the best the Russians can do is tell the world to wait...and wait...and wait...and wait...for a technologically inferior PUKE-FA.

We already invented an RLV, the first remotely operated in history. The cost efficiency of such a device discounted it. If NASA wanted too, they could have built more shuttles, but they didn't do to cost. Now they will have to pay us in our ELVs to get them into space... how ironic.

The 'R' stands for 'reusable', not remotely controlled. Again...people look at results, not speculations. People will know, through successes and failures, that the American space program, in terms of reusable vehicles, the future of manned space exploration, is superior to anything the Russian space program has. The Russian space program has a lot of medical knowledge due to zero-g long duration experiments. But with repeated shuttle launches that can carry not only more payloads but with greater variety of payloads, the American space program is more productive overall, from medicines to metallurgy to semiconductor and many more. People are more forgiving when they see an exhaustion from efforts that produces than when they see no or little productivity from noncreativity. Expendable Launch Vehicles are static technology and if we have to rely upon Russian ELVs while we regroup, people will understand that.

 

[p2prada]

We already have some measures of active cancellation.

What do you consider about the French position with regards to active cancellation using the SPECTRA. And may I know how good the SPECTRA is against other conventional jammers?

But the natural progression of cancellation would be to control the wave's properties once it impact the body, not merely negate it.

So, are you suggesting the US has been able to successfully negate hostile waves consistently, atleast in lab tests?

And please dismiss that 'plasma stealth' nonsense. It is something the Russians cooked up to make themselves look good. Plasma have its own properties and detectors can be created to process plasma derived emissions. Look up what is plasma and what it produces besides heat.

Sir, I understand that Plasma stealth is too good to be true. In case the Russians are not lying about it, are there any counters to it from the American side.

Plasma is also formed when a space shuttle or a rocket re-enters the Earth's atmosphere. So, is it not impossible to sustain plasma flow during flight?

And how does a F-22 beat the Russian OLS or passive infrared detectors?

 

[Vladimir79]

Even though everyone expects credit given when/where it is due, everyone also pay more respects for the final products than the origins of the ideas that birthed those products. When people see the F-117, F-22, F-35 and the B-2 in flight, they will not call out Ufimtsev's name in awe, they will see those aircrafts as American products. For those who are in the aviation business, specifically avionics, specifically radar, they will mentally pay their respects to Ben Johnson.

I thought it was Ben Rich... or maybe it was this guy.

“Father of the B-2” arrested - Sepia Mutiny

I crack up everytime someone say that, usually they lifted it off some press reports whose reporters have not even a shallow understanding of aviation.

So the F-117 RAM coating did not need to patched on a regular basis? News to me... and the rest of the world based in reality.

Not this nonsense again. The F-117 first flight was in 1981, flown in secret for about a decade, then public disclosure, then retirement in 2008.

First operational in 83' with a limited production run until 90'. Out of planned 250 frames, only 59 made it off the line due to a 1994 $70 million price tag. Retirement for 18+ old frames is a little premature for USAF.

The Serbian lucky shot of one F-117 was in March 1999.

Stealth shot down by a sixties missile... embarassing to say the least.

The YF-22 first flight was in 1990, the same year as the YF-22 and YF-23 fly-off competition

Not operational until 2005. No one cares about the prototype age. A four year production run is called cut short... a running theme in US stealth procurement.

So when you said 'early retirement' it is 'early' compared to what standard? The F-16 has been around for over thirty years, is that the standard?

Quite, the F-16 is the hallmark and backbone of USAF... and will be for some time. It is a very successful fighter with 4,600 built, unlike any of the stealth models USAF has or will ever field.

Even without installed weapons system, the F-22 as a low observable aircraft was clearly the superior to the F-117 nearly a decade before the Serbian lucky shot of that one F-117.

Facts...The same level or lower RCS, superior maneuverability in all flight regimes, supercruise while the F-117 was subsonic, a superior AESA radar system whereas the F-117 has no radar, superior pilot vision, superior avionics...In other words, the F-117's retirement was inevitable even before March 1999, the time of the Serbian lucky shot.

I think you are confused... the F-22 was not the replacement for the F-117. The F-22 is an air-superiority fighter with little air-to-ground capability. The F-117 was strictly a bomber, despite the ignorant designation, stealth fighter.

I do not know the origin of this 'early retirement' nonsense and really I do not care, but all it takes is less than five minutes checking out publicly available information on them and another five minutes to do some critical thinking and it would be clear to see the absurdity of that 'early retirement' argument.

Just look at the backbone of legacy USAF platforms,

F-16 - 31 yrs
F-15 - 33 yrs
B-52 - 54 yrs

... and they will still be in service for many years to come in large numbers.

As for the claim that the F-117 is 'vulnerable' to long wavelengths, I have already debunked that notion a while ago. Those who made that argument that desperate people quickly latched onto have not a clue about radar detection.

I don't know who you are talking to... but I never made that argument. Best for you to keep focused on the discussion at hand rather than making up one.

Right...The only thing Russia can do is gloat about the cost when the best the Russians can do is tell the world to wait...and wait...and wait...and wait...for a technologically inferior PUKE-FA.

Puke-fa... now thats original, but not amusing except to your obvious bias.

The 'R' stands for 'reusable', not remotely controlled. Again...people look at results, not speculations. People will know, through successes and failures, that the American space program, in terms of reusable vehicles, the future of manned space exploration, is superior to anything the Russian space program has. The Russian space program has a lot of medical knowledge due to zero-g long duration experiments. But with repeated shuttle launches that can carry not only more payloads but with greater variety of payloads, the American space program is more productive overall, from medicines to metallurgy to semiconductor and many more. People are more forgiving when they see an exhaustion from efforts that produces than when they see no or little productivity from noncreativity. Expendable Launch Vehicles are static technology and if we have to rely upon Russian ELVs while we regroup, people will understand that.

That's nice, but the US space programme has become so "decrepit" (as you like to say) they need Russians to get them into orbit. We understand, with a smile on our face and greenbacks in our pockets.

 

[gambit]

I thought it was Ben Rich... or maybe it was this guy.

My mistake...My mind was on something else. Still...Like I said...With all due respect to Ufimtsev, except for us who have relevant experience in the field, whenever people see an American 'stealth' aircraft, no one will think of Petey. If I ever meet Ufimtsev, I will certainly treat him to a nice dinner and a drink.

So the F-117 RAM coating did not need to patched on a regular basis? News to me... and the rest of the world based in reality.

How does that constitute a 'nightmare'? The hyperbolic 'nightmare' says nothing about aviation maintenance. For example, on the F-111, there is a 'flux valve' that sits atop the vertical stab. It is used for the magnetic north portion of the navigation system. This is what it looks like...

Flux Valves electrically transmit information to an aircraft's compass system about its orientation towards the Earth's magnetic field

Aircraft Compass Swing - November 2005 Issue - (Aircraft Maintenance Technology)

Compass swing — those two words bring images of a time-consuming task. Many of you are familiar with this task — sitting inside the aircraft, engines running, air conditioner off so it doesn’t disrupt the magnetic compass, as you taxi all around the compass rose, relying on your co-worker’s accuracy in lining the aircraft up with the line marked on the compass rose. In this article, we will discuss performing a compass swing as well as take a look at a new product designed to save time and headaches when performing this task.

The 'compass rose' is that pretty looking 'flower' on the corner of every map that has all the four cardinal points. The 'compass rose' is also a remote part of the flightline that is as free from metal as much as possible so as not to induce magnetic variances in the 'compass swing' procedures. If I were to focus solely on the 'compass swing' procedure of the 'flux valve', and I have done enough of them, the world would think that the F-111 was a 'maintenance nightmare'.

Same for the weight-on-wheel switches on the F-16. On the F-16, the leading edge (LE) flap rig procedures require all four weight-on-wheels (WoW) circuit breakers be opened either at the same time or in very specific sequence, something that one person cannot do. The Central Air Data Computer (CADC) on the F-4 require ejection seat removal on some versions. Every aircraft has a singular unique item that will make it stand out from other aircrafts that for those who maintain them, that something is what everyone wishes could be better designed, does not break as often, installed somewhere else, made of a different material, etc...etc...Everyone complain about something, no matter what.

The F-117 has no radar, so no need to perform any nitrogen purges on any waveguides. Unlike the F-111 and the F-14, it does not have swing wings, so there is no need to perform alignment between the hydraulic actuators that move the wings and keep them synchronized. The F-16's fly-by-wire flight control systems is in the F-117 so there is no need to do any pitch-roll assembly rigging. But its RAM coating make it unique in the world so therefore maintenance on this aircraft would attract extra attention and naturally -- a 'maintenance nightmare' whenever someone need something derogatory to say about the aircraft. You have no experience in aviation so it is understandable that you would be gullible about these things.

This is why no one who has any experience in aviation maintenance, particularly the F-117, place any value on popular media reports on the supposedly nightmarish F-117?

First operational in 83' with a limited production run until 90'. Out of planned 250 frames, only 59 made it off the line due to a 1994 $70 million price tag. Retirement for 18+ old frames is a little premature for USAF.

Your opinion. I know better.

Stealth shot down by a sixties missile... embarassing to say the least.

Spray and pray tactic. Nothing to be embarrassed about. Only those who have nothing to show would grasp at such straws. If anything, it should be the Serbs and the Russians who should be embarrassed. NATO flew about 21,000 sorties over Yugoslavia. About 4,500 of those were Suppression of Enemy Air Defense (SEAD). The US flew 60 B-2 sorties straight from continental US, Whiteman AFB to Yugoslavia, and back. But only one F-16 and one F-117 was lost through a tactic -- spray and pray -- that nobody would hold against any air force in war? Numbers do not lie. The more you harp on this, the more foolish you will look to all.

Not operational until 2005. No one cares about the prototype age. A four year production run is called cut short... a running theme in US stealth procurement.

Irrelevant. The point here is that the F-22 is a generational leap to the F-117 in basic airframe. So why should we remain with the F-117?

Quite, the F-16 is the hallmark and backbone of USAF... and will be for some time. It is a very successful fighter with 4,600 built, unlike any of the stealth models USAF has or will ever field.

Yes...The F-16 is a successful aircraft. With four years experience I will attest to that. But since when is the F-16 the standard in longevity for all USAF aircrafts? The U-2 morphed into the TR-1 but it is still a 1950s design. Same for the T-38/F-5 as that aircraft is still flying for NASA and the USAF. If an aircraft continue to serve a purpose, we will continue to use it. There is no standard for you to credibly say that the F-117 had an 'early retirement'. Based upon what? Give it up, you have no argument.

I think you are confused... the F-22 was not the replacement for the F-117. The F-22 is an air-superiority fighter with little air-to-ground capability. The F-117 was strictly a bomber, despite the ignorant designation, stealth fighter.

Wrong...How the F-117 was designated is irrelevant. The F-111 was primarily a bomber despite its capability to fire air-air missiles and it is more maneuverable than given credit. I have four years experience on it to know.

The F-22 is very much a replacement for the F-117. Same for the F-35. All three aircrafts share a common denominator -- low observability through body shaping and RAM -- with the F-22 and F-35 less reliant upon RAM. The F-117 was the first generation of this capability so naturally its military capability would be limited to dropping bombs. The F-22 can also drop bombs but its primary role will be air superiority. With such a gross disparity in capabilities, of course the F-117 would be replaced.

Just look at the backbone of legacy USAF platforms,

F-16 - 31 yrs
F-15 - 33 yrs
B-52 - 54 yrs

... and they will still be in service for many years to come in large numbers.

So what?

Here is what you failed to understand about the F-117 and its role in the larger scheme. As far as military capabilities goes, the F-117 is inferior to the F-15 and F-16. Its unique capability -- low radar observability -- restrict the TYPE of missions we will send it. It cannot fire air-air missiles like the others. Its avionics package cannot communicate with its ordnance like how the others can communicate with theirs to give initial guidance. And the list goes on.

Valuable targets are not armed. They are DEFENDED BY peripheral defense facilities such as radar guided SAM stations or fighter aircraft squadrons. The US Congress Capitol building or the Pentagon are not armed but they are very valuable. So when faced with lethal air defense, the F-117's role is to exploit its unique capability of being very low radar observable to sneak through an air defense system that is under duress from 'non-stealth' aircrafts.

So for you to bring up the longevity of these aircrafts in an attempt to explain why the F-117 is retired 'early' is absurd and reveal a lack of understanding on how military aviation really works. We have successes without the F-117 before. All the F-117 does was to give us a very specific publicly known edge over a potential adversary. With the F-22 and F-35, we now have a couple of aircrafts that are ten times more flexible than the F-117 and still share its unique capability. The F-117 was not retired because of 'nightmare maintenance' or vulnerable to long wavelengths. It was retired because something else better come along.

I don't know who you are talking to... but I never made that argument. Best for you to keep focused on the discussion at hand rather than making up one.

When you made that comment about the F-117 vulnerable to 1960s SAM, you effectively said it was vulnerable to long wavelength radars. After all, the SAM that got lucky was guided by a 1960s era Soviet junk. Best you try to think about your argument.

Puke-fa... now thats original, but not amusing except to your obvious bias.

You bet I am biased. Why should I not?

That's nice, but the US space programme has become so "decrepit" (as you like to say) they need Russians to get them into orbit. We understand, with a smile on our face and greenbacks in our pockets.

We are not supermen here. We do get worn out. Our shuttle fleet is tired and we are in a financial crunch. But like I said, people are not stupid, they can see the results and make comparisons between the productivity of the US space program versus the Soviets-Russian one. We walked on the moon. You never could. We reused our spaceships until they are tired. You never had any. People can see how embarrassing for you when you gloat at someone who ran a hundred tired laps to your one.

 

[ant80]

We are not supermen here. We do get worn out. Our shuttle fleet is tired and we are in a financial crunch. But like I said, people are not stupid, they can see the results and make comparisons between the productivity of the US space program versus the Soviets-Russian one. We walked on the moon. You never could. We reused our spaceships until they are tired. You never had any. People can see how embarrassing for you when you gloat at someone who ran a hundred tired laps to your one.

I'd like to point out that after the end of the cold war, Russia gave billions of dollars worth of research data to the US. Soviets were the first to send man to outer space. They had the Mir up and running long before the USA could achieve something similar. The only thing lacking in the Russian space program is the kind of money they haven't had since the collapse of the Soviet union. They are not lacking in technology. They also have far more experienced astronauts. Remember that the first few choices for Russian astronauts refused to go on the first trip to ISS because the American commander, who was nominated for political reasons, was far less experienced than him.

 

[gambit]

What do you consider about the French position with regards to active cancellation using the SPECTRA. And may I know how good the SPECTRA is against other conventional jammers?

SPECTRA is touted as 'active cancellation' by some but in truth and function it is not. The system is more ECM than RCS reduction. What SPECTRA does is to create a more refined version of jamming than the current ECM method.

Rafale, Dassault-Breguet

Active cancellation is a LO technique in which the aircraft, when painted by a radar, transmits a signal which mimics the echo that the radar will receive - but one half-wavelength out of phase, so that the radar sees no return at all. The advantage of this technique is that it uses very low power, compared with conventional EW, and provides no clues to the aircraft's presence; the challenge is that it requires very fast processing and that poorly executed active cancellation could make the target more rather than less visible.

The complexity of active cancellation could account for Spectra's high price tag, estimated in 1997 as "several billion francs" (equivalent to the high hundreds of millions of US dollars) for research and development. One of four Rafale prototypes was dedicated to Spectra tests, along with a Falcon 20 flying testbed. Four new large anechoic chambers were built to support the Spectra project, including one which is large and well equipped enough to operate the complete system in a fully detailed electromagnetic environment.

There are two main methods in creating the highlighted transmission:

1- Transmit a separate signal
2- Manipulate the impinging radar wave

Every time a body is 'painted' with a radar wave, any portion of that wave that bounced off that body make the body an 'emitter'. The moon does not create its own light, it merely reflect and that make the Moon an 'emitter' of sort.

What the Rafale's SPECTRA system does is item 1: To transmit a separate signal that MASK any reflected signals off its body. The equivalent would be for the Moon creating its own light source that is greater than or somehow cancel out any light that reflected off its surface. So with the Rafale's SPECTRA system, we actually have TWO signals off this emitting body:

1- Reflected signal from the original impinging radar wave.
2- The SPECTRA created signal that attempt to cancel out the first signal.

Now we will see how the SPECTRA system can fall short of its intention.

In basic pulse radar operation, we have pulses and they are in a 'train'...

Radar signal characteristics - Wikipedia, the free encyclopedia

...With these two critical items that can make or break a SPECTRA-like system if it is not well designed or attempt with inferior technology...

Pulse repetition frequency (PRF)

In order to build up a discernible echo, most radar systems emit pulses continuously and the repetition rate of these pulses is determined by the role of the system. An echo from a target will therefore be 'painted' on the display or integrated within the signal processor every time a new pulse is transmitted, reinforcing the return and making detection easier. The higher the PRF that is used, then the more the target is painted. However with the higher PRF the range that the radar can "see" is reduced. Radar designers try to use the highest PRF possible commensurate with the other factors that constrain it, as described below.

Staggered PRF

Staggered PRF is where the time between interrogations from radar changes slightly. The change of repetition frequency allows the radar, on a pulse-to-pulse basis, to differentiate between returns from itself and returns from other radar systems with the same frequency. Without stagger any returns from another radar on the same frequency would appear stable in time and could be mistaken for the radar's own returns. With stagger the radar’s own targets appear stable in time in relation to the transmit pulse, whilst the 'jamming' echoes are moving around in time (uncorrelated), causing them to be rejected by the receiver.

Every pulse train has a PRF. But no one said the PRF has to be constant even between the pulses themselves. Of course, this would make the electronics more complex and costly.

Say I transmit ten pulses (one pulse train) at the SPECTRA equipped Rafale. Say I keep the PRF between these ten pulses constant. What SPECTRA will do is analyze at least three pulses regarding each pulse's basic characteristics and record the time intervals between these three pulses. So if there are three pulses, there would be two gaps, correct? Then SPECTRA will transmit its own counter signals, not to cancel out this pulse train, but to mislead me -- the transmitting radar seeking the Rafale. The 'cancellation' bit is somewhat misleading. It is deception, not negation or destruction.

Staggered PRF is also known as 'jittering' and although it is a valid technique to avoid confusion between my own and other signals in an electronic crowded environment, as a TACTIC against targets that are trying to mislead me, PRF jittering is very good. To burden the SPECTRA system, one pulse train would have a different PRF than the previous pulse train and the subsequent pulse train. The SPECTRA system would have to wait for at least three pulses per pulse train to analyze the entire train and to create an ECM signal for that particular pulse train. There could be three echoes from those three pulses or there might not be any. That is the chance that I, the aggressor transmitter, would have to swallow. So if I transmit three pulse trains with different PRF between them, aka PRF jittering tactic, I could have up to nine echoes (or not) to try to detect the Rafale.

I could burden the SPECTRA system even more if I modulate the amplitude (strength) of each pulse in each of the three pulse trains. So each pulse train would have the same PRF between the ten pulses but each pulse would have different amplitude. That is an additional character of the entire train that SPECTRA would have to analyze and create an ECM signal. So now instead of using three pulses to analyze and create an ECM signal, SPECTRA might (or not) use four or more, giving me, the aggressor transmitter, more odds of detection, no matter how briefly, of the Rafale, before SPECTRA can respond.

Now YOU can see how the more the transmitter manipulate its own signals, the greater the burden it will be for SPECTRA and the greater the odds of detection against a SPECTRA equipped aircraft. This is limited only by your imagination and technical limitations in order to make possible your imagination. So if you are a 'Third World' air force flying Korean War vintage fighters, SPECTRA will defeat you with ease.

On the other hand, if a SPECTRA-like equipment is badly designed and built with inferior technology and material, this SPECTRA-like system can actually assist you, the aggressor transmitter, in locating the target. This inferior system can wait too long to create an ECM response, that ECM response may not effectively mask the signals that bounced off the aircraft's body, or it could even boost that reflected signal, advertising to all on the aircraft's presence.

So even though the SPECTRA system does have its limitations and weaknesses, the ECM tactic itself is sufficiently sophisticated and indeed very technologically daring that only the more technologically adept countries could afford to develop the idea. The consequences -- may be lose a war -- of a badly designed SPECTRA-like system is too disastrous to risk investment.

As for item 2: Manipulate the impinging radar wave. That is the next phase in US 'stealth' technology.

So, are you suggesting the US has been able to successfully negate hostile waves consistently, atleast in lab tests?

Yes...The current RAM method does perform some 'destructive' action on a portion of the impinging wave. It basically convert the wave to heat, but not enough to show on IR detection. The amount of the wave converted to heat is miniscule compared to in-flight friction. The rest of the wave is diverted through body shaping and I explained that already.

Sir, I understand that Plasma stealth is too good to be true. In case the Russians are not lying about it, are there any counters to it from the American side.

Plasma is also formed when a space shuttle or a rocket re-enters the Earth's atmosphere. So, is it not impossible to sustain plasma flow during flight?

I said elsewhere that there is no such thing as 'military technology' but only the military adoption and adaptation of technology for military uses. I never said that plasma could not be created through man-made methods. I am saying that the Russians grossly exaggerated the efficacy of plasma as a military tactic. They are not lying. They are just not totally honest with you.

And how does a F-22 beat the Russian OLS or passive infrared detectors?

Optical sensor, including IR, are not good for range estimation. They are best to give initial directional guidance to the weapons. They depends on target characteristics, such as reflectivity to ordinary light or IR or ultraviolet or even water vapor. In other words, optical sensors rely upon the target, as an emitter, to emit signals not under your control. Radar signals, on the other hand, are fully under your control. You determine its characteristics, when/where it will be transmitted and you know best what the results will look like because you know the initial characteristics. Optical sensors, including IR, is no greater a threat to the F-22 than radar.

 

[p2prada]

SPECTRA is touted as 'active cancellation' by some but in truth and function it is not. The system is more ECM than RCS reduction. What SPECTRA does is to create a more refined version of jamming than the current ECM method.

According to open sources, France is still fine tuning active cancellation.

Optical sensor, including IR, are not good for range estimation. They are best to give initial directional guidance to the weapons. They depends on target characteristics, such as reflectivity to ordinary light or IR or ultraviolet or even water vapor. In other words, optical sensors rely upon the target, as an emitter, to emit signals not under your control. Radar signals, on the other hand, are fully under your control. You determine its characteristics, when/where it will be transmitted and you know best what the results will look like because you know the initial characteristics. Optical sensors, including IR, is no greater a threat to the F-22 than radar.

The Russian OLS uses a laser range finder too. They have claimed that they can track any target with just the heat from friction at distances greater than 20km for air targets.

The new R-74 K-MD being developed for PAKFA with the help of the OLS is said to be able to target incoming missiles too.

 

[p2prada]

We, the US, do encourage people to believe EVERYTHING the Russians claim. From how crappy our stuff are to how great theirs are.

Something else that came to my mind is the Brahmos missile. The missile's propulsion system and seeker proves that the Russians are not just all talk and no show.

Stealth is an expensive program to undertake. Lack of funding has obviously affected their program as seen from the canceled Mig-1.44. Even the PAKFA may not have become a reality if it wasn't for Indian funding and India wouldn't have funded the program if it was not feasible. It took 6 years of study(after Russia approached us in 2002) and the deal was signed 3 years after the F-22 was operational. It should be something worth our time when we ourselves have proposed a similar program(MCA).

IAF submitted their requirement only this week.

 

[SATISH]

Well there have been a lot of research going on with stealth technologies going on in the erstwhile Soviet Union and the modern Russia. 2 TDs were rolled out and I was lucky enough to see the AL 41 test-bed. So I guess PAKFA flying next month or early next year is perfectly possible.

 

[ptldM3]

If PAK FA still isn't ready to fly by this time next year, India will withdraw from the programme and private funding will cease. Since our government is only funding 30% with direct public money and getting private stakes to cover the other 20%, the project cannot afford to continue. Further delays cannot be tolerated and charges will be brought to project management as negligence as has been threatened with Bulava.

Thats good to know.

if you are wondering why the photos are not out let let me say it makes pure business sense and sukhoi just showcased and released its SU35BM in maks 2009 having got the russian air-force order it was pushing for a bid for the indian market and also competing in the brazil-tender they did not want to get the pakfa pictures out and reduce the potential sale of of the BM on which it has invested and worked a lot pakfa early release would have killed the su-35 and sukhoi was smart enough to put the feet on both ends and thread a careful line on which their was only 1 winner and its the company itself

That makes sense; Sukhoi is protecting it's investments, so the PAK FA will be offered to other countries?

 

[ptldM3]

The one thing that certainly improved over time are the claims on how good it is going to be...

It will be good, imagine a stealthy SU-30 with AESA radar, AL-41 engines able to produce between 35,000-40,000 lbs thrust, and other state of the art goodies suchs as improved jamers, weapons...ect.

It seems you don't beleive in Russia's capabilities. Hypothetically speaking, if an American pilot got to fly the new SU-35MB against say F-15's or F-16's don't you think the SU-35 would atleast be equal? And if the SU-35 is an equivalent for anything in the US inventory, excluding the Raptor, don't you think the PAK FA would be equal or almost equal to the Raptor? Russian has the know-how and now we also have India's know-how. Trust me the PAK FA will be will be good, all we need is time.

 

[Vladimir79]

It will be good, imagine a stealthy SU-30 with AESA radar, AL-41 engines able to produce between 35,000-40,000 lbs thrust, and other state of the art goodies suchs as improved jamers, weapons...ect.

It seems you don't beleive in Russia's capabilities. Hypothetically speaking, if an American pilot got to fly the new SU-35MB against say F-15's or F-16's don't you think the SU-35 would atleast be equal? And if the SU-35 is an equivalent for anything in the US inventory, excluding the Raptor, don't you think the PAK FA would be equal or almost equal to the Raptor? Russian has the know-how and now we also have India's know-how. Trust me the PAK FA will be will be good, all we need is time.

Don't bother wasting your time asking him what he thinks of Russian capabilities... PUKE-FA reference should be clear enough.

 

[AJSINGH]

I would not place too much faith on this 'patch' created by the Russians.


The L-band is around 1ghz and in radar detection engineering, it is WELL KNOWN that nothing is really 'invisible' at 1ghz and below. Plus, we never claim our LO aircrafts are 'invisible' to start. Kopp writes good articles but sometimes I wonder if he actually writes them or one of his lackeys does. This article is one of those times.

True...That the L-band can increase the odds of detection, BUT target information such as altitude, speed and aspect angle are so coarse that the L-band is never used beyond volume search capability. When a missile is closing in on a maneuvering target that is deploying ECM techniques in trying to evade said missile, fine target information is required due to high Mach closing speed and rapidly decreasing distance. To have those fine target information, the X-band with its high freqs coupled with high pulse repetition rates are employed.

Radar Frequency Bands

The link above is an example of how different freqs are usually utilized.

Now let us take a brief look at Kopp's article...

Assessing the Tikhomirov NIIP L-Band Active Electronically Steered Array

Scroll nearly to the bottom of the article and look at the chart labelled: Detection range in nautical miles, RCS in square metres.

The F-35's RCS is somewhere on the far right of that chart, between .001 and .000 figures. Now take a look at the vertical scale -- distance. We can see that for the F-22 and F-35, this L-band AESA radar may be able to detect them only in less than 20nm, well within AIM-120 range. More likely the Su would be dead before detection. This chart's title is also revealing when we look at the word: Co-altitude. That mean same altitude. In other words, this L-band AESA radar assembly installed on the Su's wing leading edges is best when the target is at the same altitude as the Su. How absurd is that?

Then there is this hilarious attempt to find target altitude...
One does not need to be a pilot to see how impractical this is. So the alternative is to install more arrays...So now we have a monopulse operation in the L-band to try to detect a very LO object that must be at the same altitude as we are and at less than 20nm.

I am not going to go into details on how to jam a monopulse radar, especially one operating at such a low freq. Missile monopulse operation is in the X-band or higher and that is why it is more difficult, not impossible, to jam an X-band monopulse.

Our 'stealth' pilots have little to worry from this. What India should worry about is how much money to shell out for this 'snake oil'.

all that is fine but you have missed an important point .First as you claim that
" That the L-band can increase the odds of detection, BUT target information such as altitude, speed and aspect angle are so coarse that the L-band is never used beyond volume search capability
do u really think russians are stupid to use that technology when they know that band is not effective

atleats L band based radar are more effective than x band , u atleast know that something is out there and counter measures can be initiated

when u said this That mean same altitude. In other words, this L-band AESA radar assembly installed on the Su's wing leading edges is best when the target is at the same altitude as the Su. How absurd is that?
u forgot what assumptions are being made in that article
and i quote from that article itself " The model is based upon a series of reasonable assumptions about the radar design, but in the absence of hard design parameters disclosed by Tikhomirov NIIP, these are only assumptions - the actual performance of radar could be considerably better or worse depending on specific design choices and implementation constraints, including factors such as the absence or presence of STAP processing, and choices in FAR, Pd, and other cardinal parameters." there you go ,your facts are only assumptions ,plus in any combat ,interest in any target is only +- 20degree up and down

 

[AJSINGH]

While it is true that the top and underside of an aircraft provides the greatest radar return, it is actually a very low probability that such a situation could occur that would result in such a large return. To understand why, some basic information about radar detection and behavior is necessary.

First...Radar detection is a statistical process. If I have ten pulses and only two of them produced returns, the odds are very low that there is 'something' out there. If there are five returns, now I have good cause to be suspicious. If there are seven to eight returns, odss are excellent that there is a body out there. In the early days of radar detection, as in WW II, it was humans who made these statistical determination. The result was many false determinations and wasted resources on wild goose chases. Today we have machines to perform these statistical determinations.

Second...A radar signal always deflect 90deg off an ANGLED surface.

The only time a surface will produce the highest echo energy is when the transmitter is directly facing the surface. Else if the planar surface is off even slightly, the signal will deflect away from the transmitter's direction. If two (or more) surfaces (or edges) meet and formed a corner, we have what is called a 'corner reflector' and this structure also provides the highest echo energy to the receiver section of the radar system. Target corner reflectors are undesirable when the goal is to avoid detection.

But if the goal is to increase radar signature...

Corner reflector - Wikipedia, the free encyclopedia


On an aircraft, where the vertical stab meet the fuselage is a corner reflector, where the pylon meet the wing is another corner reflector. Bombs and missiles have fins and where the fins meet the weapons' bodies are corner reflectors. There are plenty of corner reflectors on an aircraft and all of them contribute to the aircraft's overall RCS average. They are undesirable. But if one surface is off perpendicular even if slightly, then we have decreased the amount of energy that can be reflected back to source direction. The SR-71's inwardly canted vertical stabs are not for aerodynamic purposes but for the elimination of externally facing corner reflectors. Compare them against the F-15's twin straight up vertical stabs for contrast.

In theory, if a surface is perfectly smooth, then as long as the surface is not perpendicular to the transmitting radar, all energy will be reflected away from the transmitter and effectively the surface does not exist as far as the radar is concerned. No surface is perfect. Small and even microscopic imperfections formed corner reflectors and these are what present the aircraft to the radar. If the radar is a ground station, the only time a surface is directly facing the radar antenna is if the aircraft is directly overhead. That situation is more likely at a busy civilian airport. It is high improbability that two opposing fighters will create this situation in their maneuvers to get into favorable firing positions. So it is corner reflectors, large from aircraft structures and small from aircraft surface imperfections, that radars will detect an aircraft.

The F-117 exploit this behavior and this is why we see the F-117's body composed largely of angled surfaces. Those sawtooth patterns where panels meet each other are also because of the desire to eliminate corner reflectors.

The underside of the F-117 is visually deceptive. It is of the 'tapered conductivity' design. Those small reflections have their energy further reduced by radar absorbent materials (RAM), leaving the remaining energy levels be dismissed by the radar as belonging to the 'clutter' region.

But there is the visual difference between the F-117, the first generation of 'stealth' design, to the next generation that has the B-2, F-22 and F-35. The F-117 is retired, not because one F-117 was shot down over Yugoslavia, the Serbs and the Russians would love people to believe that lie, but because there is another type of behavior of radar signals upon a surface that the B-2, F-22 and F-35 now exploit...

Creeping wave - Wikipedia, the free encyclopedia

When a radar signal impact a sphere or a curved surface, we have this 'creeping wave' effect where most of the wave's energy travels along the surface and finally 'leapt' off the body, hence the echo appears at a distance from the actual body. Only minor surface imperfections at the point of impact produces any reflections that could return straight to the transmitting radar.

A sphere's RCS is constant no matter which direction is the transmitting radar. Some very minor energy will be detected, but most of the signal will travel on the surface of the sphere and eventually meet on the opposite side.

For the B-2, F-22 and F-35, their RAM will reduce this specular energy to the 'clutter' region and be dismissed by the enemy's radar as junk. By the time there is sufficient energy level for the radar to statistically determine that there is an aircraft out there, it would have been weapons release time for these 'stealth' aircrafts. For the F-22, the enemy fighter would not be aware of any threat.

An airliner is a 'cooperative' target. The airliner wants to be seen, not only does its shape is conducive to radar detection, but it also carries a transponder to advertise its presence to all. Military aircrafts are mostly 'noncooperative' because of their mission, which is to try to destroy the enemy. Currently, the B-2, F-22 and F-35 are the least cooperative, or the most noncooperative, shapes in the air. They fly with transponders to assist controllers and to mask their true RCS.

all that is fine , i know what your are talking about
when you said While it is true that the top and underside of an aircraft provides the greatest radar return, it is actually a very low probability that such a situation could occur that would result in such a large return you are underestimating combat situation ,raptor may have to gain altitude and pull up the nose hence showing the belly to Su 35 radar ,so there you go ,u have large radar return
plus if we go laws of reflection for any electromagnetic rays .angle of incidence =angle of reflection . hence if the radar rays is incident at 30degrees it will reflect by 30degrees. therefore your statement Else if the planar surface is off even slightly, the signal will deflect away from the transmitter's direction is not true .

also remember the MIG 31 with 1 ton PSEA radar . why do u think america retired its SR 71 fleet because new soviet interceptor was in place .the radar output power for MIG 31 was so high that it could have burned through SR 71 ECM equipment .plus MIG 31 radar case the desgin philosophy was very simple yet affective ,il try to explain .consider that i have a footalll and a wall in front of me,the wall is highly paded and shock absorbing springs are attached to hit .i kick the football with 20% of my energy ,the chances of football comming back to me after hitting the wall is quite low but if i hit with 110% of my energy the chnaces of the ball comming back to me are pretty high .take that example and fit it in the case of radar ,more powerfull radar waves the more chances of stealth being defeated

also about the case in which serbs managed to shoot down F-117 was not luck or anything else ,it just proved the fact that no stealth is fail proof and even 1960 vintage radar can shoot down F-117

 

[AJSINGH]

plus after the fall of soviet union many scientist who were working for the stealth project ,immigrated to america. if anyone wants to know more i will paste the links.Plus the very reason america started its ATA ( advance technology aircraft ) was becaise they had found that the Mig 29 and Su 27 series was better than their F-15 ,F-16 ,F-18